Effective methods for the recovery and/or separation of particular transition and post transition metal cations from each other and from other cations from solutions thereof, admixed with chelating agents and/or other ions which may be present, represent a real need in modern technology. As specific examples, efficient and economical separation of (1) ppm levels of Sb from concentrated Cu, Ni, Zn, Ag, or other metal cations under acidic conditions; (2) separation of Zr(IV), Pu(IV), and Hf(IV) from HNO.sub.3 solutions containing large amounts of other metal cations; and (3) separation of Cu, Ni, Fe, Zn, Cd, Ag, Pb and Hg as toxic wastes from potable water or industrial effluents, all represent real separations needs with presently either unsatisfactory technologies for their accomplishment, or for which more economical technologies are desired. These ions are often present at low concentrations in solutions containing other ions at much greater concentrations. Hence, there is a real need for a process to selectively concentrate and recover these ions.
It is known that molecules containing amine and phosphonic acid groups show strong and somewhat selective interactions with lanthanides, Ga, Sb, Bi, Mn, Fe, Co, Ni, Cu, Fe, Zn, Al, Hg, Pb, and Ag under mildly acidic or neutral to basic Ph conditions. These molecules also show highly specific selectivity toward Sb(III), Zr(IV) and other 4.sup.+ metal cations under acidic conditions.
The process of the invention is particularly adaptable to the removal of Sb(III) from H.sub.2 SO.sub.4 streams containing high concentrations of plating metal cations such as Cu(II) and of Zr(IV) and Pu(IV) from nitric acid streams.
The products and processes described in the present invention overcome virtually all of the difficulties described above and provide an effective means for the practical separation of desired ions.